Alternative RUTF formulations (Special Supplement 2)

By Steve Collins & Jeya Henry

Developing CTC programmes that use Ready to Use Therapeutic Food (RUTF) made locally, from locally available produce, and used to treat malnutrition and HIV amongst the local population, is an important vision for the future of CTC. This article describes research work into developing new RUTFs.

Basis of RUTF

To date, the commercial forms of RUTF are either BP100, a compressed biscuit made by Compact, or Plumpy nut, an oil based paste developed by IRD and Nutriset in France (22). Technology to make compressed biscuits is complicated and expensive and not transferable to small scale manufacturers in developing countries. By contrast, oil based pastes such as Plumpy'Nut can be made using simple technology that is easily transferable to small scale local producers in developing countries. Plumpy'Nut is made from peanuts, sugar, milk powder, vegetable oil and a vitamin mineral mixture. Although this combination of ingredients produces a product that is very well suited to the treatment of acute malnutrition, the recipe has several features that decrease its suitability as a candidate for widespread local production. Milk powder is expensive and often must be imported - in Malawi the cost of milk powder represents over half the cost of the final RUTF. Peanuts are also notorious for being contaminated with aflatoxin and this greatly complicates the quality control of small scale production. There is also growing concern about allergic reaction to peanut and their high phytate:zinc ratio (which increases the risks of binding all micronutrients) thereby reducing their suitability.

The idea of developing local, low cost RUTF, rich in protein, energy dense and suitable for feeding to young children and other vulnerable groups, arose in the early 1950s largely due to the work of Jelliffe (1955) and Brock (1961). The simplest recipe for RUTF is one which has only two ingredients, for example a cereal or root mixed with a legume. However, other foods must be added to this basic mix in order to make a multimix that is nutritionally suitable for the treatment of acute malnutrition. A nutritionally suitable multimix for RUTF has four basic ingredients:

A staple as the main ingredient - preferably a cereal.

A protein supplement from a plant or animal food - beans, groundnuts, milks, meats, chicken, fish, eggs, etc. To be practical such foods must be low-cost, and this requirement has pushed development towards legumes and oilseed as these are cheaper than products containing milk or other animal products.

A vitamin and mineral supplement - a vegetable and/or fruit.

An energy supplement - fat, oil or sugar to increase the energy concentration of the mix.

In addition, an ideal RUTF formulation must have the following attributes:

Product development

Numerous cereal, legume and oilseed mixtures were evaluated on the basis of the above criteria. In particular, efforts were made to combine the various cereal, legume and oilseed mixtures to maximise the protein quality, attempting to offset any essential amino acid deficiencies in one ingredient by combining it with another ingredient that was high in that particular amino acid. This process led to a list of 13 products that had reasonable theoretical properties. Following numerous products development trials, the list was reduced to three potential alternatives. The foods were prepared from roasted or processed ingredients with total exclusion of water. They had low dietary bulk, low potential for bacterial contamination and were ready to eat without cooking. Similarly, the commodities chosen had the most appropriate energy density and high biological value of protein. Moreover, the proposed foods had an optimal physical characteristic of being soft in consistency, easy to swallow and suitable for infant feeding1. The three most suitable recipes were:

It is important to emphasise that the cereals, legumes and oilseeds were all roasted prior to the milling into flour, as the use of raw non-roasted commodities could lead to the presence of potentially high levels of anti-nutritional factors and phytates. In keeping with the recommendation of the UN nutritional standards (Codex) sunflower oil was used in all products in order to meet (n-3) and (n-6) fatty acids requirement. It is usually specified that at least 3 to 10% of total energy should be provided by (n-6) fatty acids and 0.3 to 2.5% by (n-3) fatty acids.

*Protein and fat are reported to contribute 11% and 57% in energy input. Total energy is reported to be 530 kcal/100g and moisture < 5%.
**The energy has been calculated using Atwater factors.
***Carbohydrate is by difference assuming protein to be nitrogen (N) times 6.25.

Table 16: Mineral analysis for RUTF products

RUTF-1

RUTF-1

RUTF-3

Plumpy'nut®

mg/kg

mg/kg

mg/kg

mg/kg

Cu

2.1

2.1

1.8

1.7

Zn

10.9

10.9

10.2

13

Ca

338.1

338.1

209.8

310

Na

256.5

256.5

189.9

<290

Mg

118.4

118.4

119.1

86

Fe

5.6

5.6

4.4

12.45

Table 17: Water activity (aw) in 3 RUTF samples

RUTF samples

Water activity

Rice-Sesame (RUTF-1)

0.290

Barley-Sesame (RUTF-2)

0.279

Maize-Sesame (RUTF-3)

0.260

Plumpy'nut®

0.241

Analytical Studies

To ensure that the products were safe and appropriate for field testing, macro nutrient and micronutrient composition, water activity, levels of microbial contamination and indices of rancidity (free fatty acids and peroxide values) were tested. The results (presented in tables 15, 16, 17 and 18) demonstrated that the nutritional composition, with the exception of iron, of each of the new RUTFs is close to Nutriset's Plumpy'Nut®. The products are palatable, stable and microbiologically safe.

Using the basic formulation outlined above, it would be easy to alter the amount of macronutrient and/or micronutrient of the products by varying the oilseed-cereal-legume combinations and/or the mineral and vitamin mixture. The low level of iron could be easily rectified by increasing the level of iron added to the premix. Table 18 demonstrates that the three new products have low water activity, similar to that of dried coffee, and below the level required to support any form of bacterial or even fungal growth. This finding was supported by bacterial analysis that demonstrated that for all the pathogens tested, the results were within microbial specification for this type of food.

These studies demonstrate the potential of new RUTF, produced from locally available grains and legumes, without the addition of milk powder or peanuts. Eliminating milk powder and peanuts and using local grains should allow these products to be made very much more cheaply than the $3,500 USD / MT that Nutriset charge for Plumpy´nut®, and more cheaply than the $2,000 USD / MT cost of the locally made peanut-based equivalent in Malawi (see section 5.21). Clinical field trials are now being conducted in Malawi, to compare the effectiveness of these new RUTFs with locally made RUTFs that include peanuts and milk powder, in treating severely malnourished children.

Table 18: Interaction between aw and microbial proliferation in some foods

Water activity

Foods

Microorganisms

0.98

Fresh meats, Fish, vegetables, Milk

Most food spoilage and food-borne pathogenic organisms grow

0.85 - 0.60

Flour, cereals, Nuts

No pathogenic bacteria grow

0.60

Confectionery, noodles, dried Milk

Microorganisms do not multiply but can remain viable for long period

0.30 - 0.20

Biscuits, Instant coffee

No viable microbial growth

Source: Peter Fellows (2000)

Future developments

These new RUTFs are eaten uncooked and have a low water content. This makes them suitable vehicles to deliver not only vitamins/antioxidants, but also probiotics and prebiotics (see box).

Synbiotic enhanced RUTF, designed with high levels of certain micronutrients, have recently been shown to slow the progression of HIV/AIDS. These may have huge potential in the treatment of HIV/AIDS, as well as acute malnutrition and a whole range of other illnesses and post operative conditions associated with diarrhoea and wasting, in particular. The current trial in Malawi is therefore also examining the effect of adding a mixture of probiotic and prebiotics called Synbiotic 2000 forte (Medipharm AB, Kågeröd, Sweden) into the new RUTF. In this study it is planned to test the effectiveness of synbiotics in combination with RUTF, in the treatment of patients recovering from severe malnutrition. As severe acutely malnourished children have features of immuno-suppression similar to some of those found in HIV/AIDS, it is hoped that this study will also provide initial evidence into the feasibility of using RUTF-synbiotic combinations, to slow the progression of HIV.

What are probiotics and prebiotics?

Probiotics are usually bacteria from the lactobacillus family
that have at least five beneficial therapeutic functions:
They reduce or eliminate a range of potentially pathogenic
micro-organisms
They reduce or eliminate various toxins, mutagens,
carcinogens, etc.
They modulate the innate and adaptive immune defence
mechanisms.
They promote apoptosis (the process of programmed cell
death or cell suicide).
They release numerous nutrient, antioxidant, growth,
coagulation and other factors necessary for recovery (28).
Prebiotics are generally polysaccharides, plant fibres that
are resistant to digestion by human digestive enzymes.
They exhibit strong bio-activity, exerting their effect
through increasing the adherence of non-pathogenic
bacteria to intestinal mucosal cells and via the generation
of beneficial short chain fatty acids in the large intestine. Recent studies have demonstrated that when taken orally
prebiotics can assist in recovery from infectious diarrhoea
(29).

Recent results from prospective controlled trials in post
operative surgical patients and after transplantation and
immuno suppression, suggest that combinations of pre
and probiotics, referred to as 'synbiotics', can reduce
greatly the incidence of post operative infection, shorten
recovery times and reduce the need for antibiotics
(24;25). Other researchers have demonstrated benefits of
probiotics in the treatment of lactose intolerance, viral
diarrhoea and antibiotics-associated diarrhoea (26).